Heart Failure and Cardiac imaging Flashcards
Causes of heart failure. What is the effect of heart failure?
Structural or functional problem with ventricular filling or ejection of blood.
Ultimate effect = decreased cardiac output
State the categories of heart failure. What’s the difference between HFrEF and HFpEF?
HFrEF >> HF due to reduced ejection fraction
HFpEF >> impaired LV diastolic function
Impaired RV systolic function
Valve disease
What are some of the symptoms of heart failure?
DOPFEL
Dyspnea
Orthopnea
Paroxysmal nocturnal dyspnea
Edema
Fatigue
Limited capacity for exertion
What are the clinical symptoms for patients with chronic low EF?
Enlarged heart (dilated Left Ventricle)
Low blood pressure, elevated HR
Poor circulation (cool extremities)
Fluid retention
Explain how the body tries to compensate for the decreased cardiac output seen in pts with heart failure
low CO >> low BP (MAP = CO x TPR) >> Reflex activation (inc. Angiotensin 2 >> Sympathetic activation) >> Increased vascular tone >> Vasoconstriction (increased afterload) >> further decreased Cardiac output
How do HF pts get pulmonary edema?
Increased LV pressure >> inc LA pressure >> inc pulm vein press (greater than interstitial pressure) [fluid moves from high press to low press env); fluid leaves pulm space and enters interstitial space and one gets pulmonary edema
What would cardiac function curve look like for normal pts vs pts w/ HF?
Strategies to improve cardiac output
Increase HR
Decrease afterload
Increase contractility using catecholamines/inotropic drugs
Calcium sensitizers + Myosin activators
Outline the mechanism by which catecholamines increase contractility (hint: involves phosphorylating Ca channels and phospholamban)
How does Digitalis work to increase contractility?
Digitalis blocks Na/K pump >> inc intracellular Na conc >> reverses NCX (Na kicked out while Ca pumped in) >> raises intracellular Ca conc >> more Ca2+ goes to SR so more Ca available for contraction
What are the effects of PKA signaling on force generation?
Higher peak force (more Ca = more force of contraction)
Faster relaxation (b/c of Phospholamban i.e. calcium being sent to SR)
How do Ca sensitizers work?
Inc Ca sensitivity w/o increasing Ca concentration (myofibers more sensitive to Ca2+ so less of it is needed for the same level of contraction)
How do myosin activators increase contractility?
Draw a PV loop explaining the difference between HFpEF and HFrEF
HFpEF: no heart enlargement, diastolic volume = normal but small changes in volume = big change in LV pressure; contractility = normal; SV = normal
HFrEF: reduced contractility, LV enlargement; SV = normal
Define ischemia. What is the ischemic threshold?
O2 supply cutoff (when there’s a demand-supply mismatch)
Ischemic threshold: blood flow level below which indicates reduced O2 delivery
Manifestations of ischemia
Reduced blood flow>>diastolic dysfunction>>systolic dysfunction>>ECG abnormalities>>clinical symptoms
What is the action of adenosine upon binding to the A2A receptor? What about A2B and A1/A3?
Coronary vasodilation (also peripheral, but mostly coronary)
a2B binding: peripheral vasodilation
a1/a3: vessel constriction
Draw and describe a PV loop comparing systolic heart failure and diastolic heart failure to normal heart function
What are the hemodynamic changes that occur with aging? (what is an increase in stroke volume more dependent on? what happens to ejection fraction in an aged heart?)
